A flat panel sensor is a device for converting incident light, such as X-ray, visible light or infrared light, into an electrical signal according to the intensity of the incident light. When incident light is reflected by or transmitted through an object, effects of absorption, reflection and scattering occur. Because of different structures in different regions of the object, light reflected by or transmitted through the different regions of the object may have different intensities, which can be represented through a flat panel sensor, thus a grayscale diagram showing corresponding relations between the incident lights and surfaces or inner structures of the object is formed to facilitate analysis of the object. The flat panel sensor is widely used in the field of healthcare, safety inspection and industrial non-destructive detection because the flat panel sensor can effectively carry out non-destructive detection of objects.